The platform I’m building needs to facilitate electronic transfer of funds of between $20k and $20m at a time ($AU). Clients (both sides of the transaction) will initially be limited to Australia

Can I please get your thoughts and recommendations on the following three things:

Security - optimum bank account integration method

Fee models of different providers (e.g. from what I can tell the fee model for Plaid and Stripe seems to be for smaller transaction amounts, and I’m not even sure if these are the right tools?)

Any pre-existing plugins that supports 1&2 above - and if not, whether you know of another intermediary that might eliminate the need for me to build separate APIs with each Australain banking institution… (which isn’t feasible)